Grinding machines are used to flatten surfaces of machine parts. In a known grinding machine, a parts carrier is located between two grinding wheels, i.e., an upper grinding wheel having an upper planer grinding surface and a lower grinding wheel having a lower planer grinding surface. The known parts carrier assembly consists of a fixed outer ring, a driven inner pinion, and toothed planet wheels all located between the upper grinding surface and the lower grinding surface of the respective grinding wheels. The parts to be ground are located in sockets found in the toothed planet wheels.
Such a grinding machine provides adequate results; however, loading and unloading of the grinding machine can require a significant amount of time because the plurality of toothed planet wheels that must be loaded into and unloaded from the grinding machine.